U.S. patent application number 09/928160 was filed with the patent office on 2001-12-27 for progressive brake light system.
Invention is credited to Cohen, Saul Lawrence, Gordon, Larry Rubin, Kessel, Gary Nathan.
Application Number | 20010054957 09/928160 |
Document ID | / |
Family ID | 10845785 |
Filed Date | 2001-12-27 |
United States Patent
Application |
20010054957 |
Kind Code |
A1 |
Cohen, Saul Lawrence ; et
al. |
December 27, 2001 |
Progressive brake light system
Abstract
The progressive vehicle brake light system of the invention
consists of a brake sensor arranged to sense the travel of a brake
pedal and a brake light display arranged to illuminate or
extinguish in sequence or progressively in response to the travel
of the brake pedal. A microcontroller is provided for receiving a
signal from the brake sensor and controlling the brake light
display accordingly. The brake sensor is typically an optical
sensor utilising infrared transmitters and receivers arranged to
sense the distance and direction of travel of the brake pedal. The
brake light display consists of a row of light emitting diodes
(LEDs) which are arranged to illuminate from the opposite ends
towards the middle as the brake pedal is depressed and to
extinguish in reverse sequence when the brake pedal is
released.
Inventors: |
Cohen, Saul Lawrence;
(Johannesburg, ZA) ; Kessel, Gary Nathan;
(Johannesburg, ZA) ; Gordon, Larry Rubin;
(Johannesburg, ZA) |
Correspondence
Address: |
Dean W. Russell
KILPATRICK STOCKTON LLP
Suite 2800
1100 Peachtree Street
Atlanta
GA
30309-4530
US
|
Family ID: |
10845785 |
Appl. No.: |
09/928160 |
Filed: |
August 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09928160 |
Aug 10, 2001 |
|
|
|
PCT/GB99/00431 |
Feb 11, 1999 |
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Current U.S.
Class: |
340/479 ;
340/463 |
Current CPC
Class: |
B60Q 1/444 20130101 |
Class at
Publication: |
340/479 ;
340/463 |
International
Class: |
B60Q 001/22 |
Claims
1. A progressive brake light system for a vehicle comprising:
sensor means arranged to sense the degree of application or release
of the brakes of the vehicle; a brake light display arrangement
comprising a plurality of individual lights or light units arranged
to be illuminated or extinguished in sequence or progressively, in
response to the degree of application or release of the brakes,
respectively; and a control means for receiving a signal from the
sensor means and controlling the sequence of illumination or
extinguishment of the lights or light units, the control means
including setting means for setting the system in relation to the
respective distance the brake pedal for a particular vehicle is
arranged to travel and/or the braking profile of the particular
vehicle.
2. A system according to claim 1, wherein the sensor means is an
optical sensor arranged to sense the movement or displacement of
the brake pedal as it is depressed or released.
3. A system according to claim 2, wherein the optical sensor
comprises two pairs of opposed infrared emitters and receivers
arranged respectively to sense the movement of a slotted or
apertured wheel or bar passing through the respective infrared
beams when the brake pedal is depressed or released.
4. A system according to claim 1, wherein the brake light display
arrangement comprises a single row of lights arranged to light up
progressively from each end towards the middle, the greater the
application of the brakes the greater the number of lights that is
illuminated.
5. A system according to claim 4, wherein the lights are light
emitting diodes (LEDs).
6. A system according to claim 1, wherein the control means
comprises a control module or unit comprising a microcontroller and
ancillary circuitry arranged to control the logical functions of
the system, including the setting means.
7. A system according to claim 1, wherein the system is linked to
an existing brake light switch, the system being activated only
once the brake light switch has been triggered.
8. A system according to claim 1, wherein the system includes a
brake switch backup mode so as to continue operating the brake
light display during brake switch failure.
9. A system according to claim 1, wherein the brake light display
arrangement is configured to illuminate and extinguish in rapid
succession when the brakes are applied fully in an emergency
braking situation.
Description
BACKGROUND TO THE INVENTION
[0001] This invention relates to a progressive brake light
system.
[0002] The use of a so-called third brake light in motor vehicles
has become popular in recent times. The third brake light is
typically positioned so as to be more visible to a driver of a
following vehicle. However, the use of this third brake light does
not alleviate a problem associated with braking in general and that
is the problem of a following driver not being able to determine
whether the vehicle in front is being braked lightly or being
braked under emergency conditions.
SUMMARY OF THE INVENTION
[0003] According to the invention a progressive brake light system
for a vehicle comprises:
[0004] sensor means arranged to sense the degree of application or
release of the brakes of the vehicle.
[0005] a brake light display arrangement comprising a plurality of
individual lights or light units arranged to be illuminated or
extinguished in sequence or progressively, in response to the
degree of application or release of the brakes, respectively;
and
[0006] a control means for receiving a signal from the sensor means
and controlling the sequence of illumination or extinguishment of
the lights or light units, the control means including setting
means for setting the system in relation to the respective distance
the brake pedal for a particular vehicle is arranged to travel
and/or the braking profile of the particular vehicle.
[0007] The sensor means is preferably an optical sensor arranged to
sense the movement or displacement of the brake pedal as it is
depressed or released.
[0008] The sensor typically comprises two pairs of opposed infrared
emitters and receivers arranged respectively to sense the movement
of a slotted or apertured wheel or bar passing through the
respective infrared beams when the brake pedal is depressed or
released.
[0009] The brake light display arrangement preferably comprises a
single row of lights arranged to light up progressively from each
end towards the middle, the greater the application of the brakes
the greater the number of lights that is illuminated.
[0010] The lights are preferably light emitting diodes (LEDs).
[0011] The control means typically comprises a control module or
unit comprising a microcontroller and ancillary circuitry arranged
to control the logical functions of the system, including the
setting means.
[0012] In one version of the invention, the system is preferably
linked to an existing brake switch, the system being activated only
once the brake switch has been triggered.
[0013] In an alternative version of the invention, the system
includes a brake switch backup mode so as to continue operating the
brake light display during brake switch failure.
[0014] The brake light display arrangement is preferably configured
to illuminate and extinguish in rapid succession when the brakes
are applied fully in an emergency braking situation.
[0015] An embodiment of the invention is described in detail in the
following passages of the specification which refer to the
accompanying drawings. The drawings, however, are merely
illustrative of how the invention might be put into effect, so that
the specific form and arrangement of the features shown is not to
be understood as limiting on the invention.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0016] The invention will now be described in more detail, by way
of example only, with reference to the accompanying drawings in
which:
[0017] FIG. 1 is a schematic block diagram of a progressive brake
light system according to the invention;
[0018] FIG. 2 is a software flow chart for the progressive brake
light system of FIG. 1;
[0019] FIGS. 3a and 3b are software flow charts of a primary learn
function of the control module of the progressive brake light
system of FIG. 1;
[0020] FIGS. 4a and 4b are software flow charts of an auto-update
learn function of the control module of the progressive brake light
system of FIG. 1; and
[0021] FIGS. 5a and 5b are software flow charts of a brake switch
backup learn function of the control module of the progressive
brake light system of FIG. 1.
DETAILED DESCRIPTION OF INVENTION
[0022] The crux of the invention lies in providing a light
arrangement which is arranged to illuminate or extinguish in a
pre-determined sequence in response to the degree of application of
the brakes of a vehicle, and in particular to a control module that
is able to "learn" the individual characteristics of the brake
pedal for a particular vehicle so as to control the illumination
and extinguishing of the light arrangement.
[0023] Referring to FIG. 1, the essential components of the
progressive brake light system of the invention consist of a brake
sensor, control module and bar display or brake light display which
is arranged to work in conjunction with an existing brake light
switch of the vehicle.
[0024] Various sensor options such as optical sensors,
potentiometer or resistance sensors, speed transducers and
accelerometers, strain gauges and linear displacement sensors, for
example, can be used. The preferred sensor, however, is an optical
sensor of the type commonly used in a PC mouse to control the
cursor on a computer screen.
[0025] The optical sensor in question consists of two pairs of
opposed infrared emitters and receivers arranged to emit and
receive respective infrared beams through which a slotted wheel
rotates. The slotted wheel is fixed to a spring-loaded hub onto
which a cable is attached. In use, the sensor is mounted to a fixed
point on the vehicle and the free end of the cable attached to the
brake pedal, or vice versa. As the pedal is depressed the cable is
wound around the spring-loaded hub causing the hub (and thereby the
slotted wheel) to rotate. As the slotted wheel rotates through the
respective infrared beams, the number of pulses is recorded which
is translated to linear displacement to sense the travel distance
of the pedal. The infrared emitters and receivers are arranged in
such a way as to provide an approximately 90-degrees offset to
enable direction to be determined as well as distance.
[0026] The progressive brake light system is linked to the existing
brake light switch which is a piece of original equipment that is
fitted to standard types of motor vehicles. The switch is used to
activate the rear brake lights of a motor vehicle when the brake
pedal is depressed. In one version of the invention, only once the
existing brake light switch has been triggered will the system
become active.
[0027] The control module which provides the heart of the system
consists of a microcontroller and ancillary circuitry which is
arranged to perform all of the logical functions of the system.
Thus, the control module will receive a signal from the brake
sensor when the brake pedal is either depressed or released and
control the illumination of the bar display or progressive lights
in accordance with the signal received.
[0028] The brake light display arrangement consists of a single row
of LEDs (light emitting diodes) which, in use, are fitted to the
rear of the vehicle to display the progressive stages of
braking.
[0029] The brake light display is arranged such that the LEDs are
illuminated progressively from the outer ends towards the middle
thereof in response to the amount of pressure applied to the brake
pedal. Thus, if the brake pedal is only lightly touched, only a few
of the outer LEDs will light up. On the other hand, if the brake
pedal is depressed fully, such as in an emergency braking
situation, all of the lights will light up in sequence from the
outside towards the middle.
[0030] Although it is not essential that the LEDs illuminate from
the ends towards the middle, this is preferred from a practical
point of view as the length of the third brake light is immediately
discernible when the brake pedal is depressed and the degree of
pressure applied to the brake pedal can be gauged by the number of
lights being illuminated in relation to the total length of the
third brake light. Alternatively, if it is a requirement that the
lights are illuminated from the middle, the outer lights may also
be illuminated as a reference point.
[0031] In a preferred version of the invention, motion of the light
illuminating from the outer ends inwards is repeated rapidly in the
event of an emergency braking situation with the pedal fully
depressed. This not only raises awareness of the light but also
distinguishes it from other conventional third brake lights. In
addition it will remain in this mode until the brake pedal is
completely released so as to retain the warning to approaching cars
that an emergency brake was necessary.
[0032] Referring to FIG. 2, it can be seen that in this version
only once the existing brake light switch has been triggered will
the system become active. The system will now check the brake
sensor for any movement of the brake pedal. If movement is
detected, the control module will either light up or switch off
respective lights on the brake light display to indicate whether
the brake pedal is being depressed or released and the amount of
pressure still applied to the brake pedal. If the brake light
switch becomes inactive at any stage, such as when the brake pedal
is released completely, the system will deactivate thereby
switching off all of the lights of the brake light display.
[0033] Although originally envisaged for the aftermarket or
retrofit market, in order for the system to be effective in
practice, it is preferable that the control module includes setting
means in the form of a "learn function" to "learn" the travel
distance of the brake pedal of a specific vehicle and/or its
braking profile. The `learn function` offers essential flexibility
required to determine the optimal settings/parameters on
installation of the system. It also ensures, through continuous
monitoring, that these settings remain relevant and accurate
through the life of the system, accommodating wear and tear,
detecting brake switch failure, and automatically adjusting the
stored settings to account for a new brake switch replacing the
faulty one. Whilst for the purpose of the present invention the
learn function is divided into three broad categories, the desired
flexibility of the feature should not be limited to these three
categories. In this regard, the three broad categories are the
primary learn function, an `auto-update` learn function, and a
`brake switch backup` learn function.
[0034] Referring to FIGS. 3a and 3b of the accompanying drawings,
the primary learn function is started 10 by pushing the appropriate
learn button of the system, which engages the primary learn mode.
If, upon polling the learn button 12 the learn function is not
engaged 14, this polling is repeated until the learn function
button is pushed 16. Once engaged, a mode counter is started and a
mode timer set 18. Depending on how long the button is pushed, one
of three modes will be engaged 20. The three different modes
reflect the different braking effects or braking profiles found on
vehicles relative to the brake pedal depression. These are 1) more
effective braking at the beginning of the brake pedal depression,
followed by less effective braking towards the end: 2) less
effective braking at the beginning of the brake pedal depression,
followed by more effective braking towards the end; and 3) a linear
braking effect in relation to the brake pedal depression.
[0035] The system display will flash a certain number of times to
indicate which of the modes has been selected. Once the correct
mode has been selected, the learn button is released. The system
will poll the learn button 22 to determine if the learn button has
been released, If not released 24 the system will determine if the
mode timer has completed its function 26. If not 28, the system
will once again poll the learn button 22. If the timer has
completed its function 30, the next mode will be invoked and
increment the mode counter accordingly 32. This process will
continue until, upon polling the learn button 22, the system
detects that the learn button has been released 34. Once the learn
button has been released, the mode timer stops and the appropriate
mode is determined 36.
[0036] In a preferred version of the invention, each mode will have
a corresponding formula/ratio for `allocating` the travel distance
input according to the braking pattern inferred from the mode
selected. By way of example, if mode 1 is selected, a 35:66 ratio
may be invoked which would have the following processing
implication: as the pedal travels 35% of the total travel distance,
the first 3 (lower segments) out of 6 segments will illuminate, and
similarly as the pedal travels the remaining 65%, the last 3
(upper) segments will illuminate. Mode 2 may have a ratio of 65:35
and mode 3 a ratio of 50:50.
[0037] Once the mode has been determined, the brake pedal is
depressed and the brake switch polled 40. If not active 38, the
system continues to poll the brake switch until activity is
detected. Once active 42, it then clears a displacement counter 44
and looks for movement of the optical sensor 46. If no movement is
detected 48, the brake switch is once again polled 50. If not
active 54, check display counter for minimum value required for a
valid `learn` 56. Since there has been no movement from first
activation of the brake switch until its release, the value (being
zero) will not be acceptable 58, hence the display will flash an
appropriate number of times, typically 5 times, to indicate an
invalid learn function 60, and end learn function 62. If, however,
the brake switch remains active 52, the optical sensor is again
polled 46.
[0038] Where movement of the optical sensor is detected 72, such
movement will determine which direction constitutes a push and
hence which direction constitutes a release. Accordingly, the
display counter may be incremented and the direction of movement
set 74.
[0039] The optical sensor is once again polled 76. If no movement
is detected 78, the brake switch is polled 80. If no activity is
detected 82, the display counter minimum value requirements are
checked 56 and the process continues until the primary learn
function is ended 62, as described above. If activity of the brake
switch is detected 84, the optical sensor is again polled 76 until
movement is detected.
[0040] Once movement of the optical sensor is detected 86, the
system detects the direction of movement. If positive 88, the
display counter is incremented 90. If negative 92, the display
counter is decremented 94. Once the pedal is released, the highest
positive displacement value is stored in RAM (Random Access Memory)
96. This value is then compared with the minimum value requirement
56, and once again the process continues until the primary learn
function is ended 62.
[0041] Turning now to FIGS. 4a and 4b, the auto-update learn
function 110 is an ongoing learn function designed to detect when
the stored maximum travel distance of the brake pedal has been
exceeded (due to wear and tear) in which case it updates the
non-volatile memory with the greater value.
[0042] Once the displacement counter has been set 112, the system
monitors the optical sensor for movement 114. When detecting
movement 116, it will determine if it is in a positive direction
118, in which case it will increment the displacement counter 120
and likewise when detecting movement in a negative direction 122 it
will decrement the display counter 124. The maximum displacement
counter value is then saved to RAM 126. The brake switch is then
polled 128. If activity of the brake switch is detected 130, the
system continues to monitor the brake switch in accordance with the
above process steps. If no activity is detected 131, and upon
release of the brake pedal, this maximum value in RAM 126 is then
compared to the parameters stored in non-volatile memory 132. If
the RAM value is less than the non-volatile memory 134, it ends the
auto-update learn function 136. If, however, the maximum value
stored in RAM exceeds the parameters stored in non-volatile memory
138, then new segment values are calculated 140 based on this
greater value. These new values are saved to non-volatile memory
142 and the current run parameters are updated 144, whereupon the
auto-update learn function is ended 136.
[0043] Referring to FIGS. 5a and 5b, the brake switch backup learn
function 210 is a learn function designed to provide a backup to
the brake switch in the event of a faulty brake switch, which
backup mode is continually checked for activity 212.
[0044] In normal operation, the backup mode is not active 214. The
optical sensor is polled for movement 216. As with normal
operation, where movement is detected 218, positive direction 220
would increment the displacement counter 222 and negative direction
224 would cause it to decrement 226.
[0045] The maximum value is again stored in RAM 228. As it
increments the displacement counter 222 it polls the brake switch
230 to check if it has been triggered. If active 232, it ends the
brake switch backup learn function 234. The system continuously
compares the displacement counter value to the stored trigger point
of the brake switch 235 (stored in non-volatile memory). If it
reaches or exceeds the stored trigger point 236 without having
received a brake switch signal 238, it will assume that the brake
switch is faulty and engage the brake switch backup mode 240, which
it will save to non-volatile memory 242. If the stored triggered
point is not reached or exceeded 244, it continues the process
until or if the stored trigger point is exceeded.
[0046] Where the stored trigger point has been exceeded, and the
backup mode invoked, it will continue to operate in the backup mode
246. This will involve polling the optical sensor 248 for movement
and illuminating the display unit accordingly. Therefore the
display will continue to operate when the factory fitted brake
lights will not. Where movement of the optical sensor is detected
250, it once again determines direction of movement. Positive
direction 252 results in the displacement counter being incremented
254, negative movement 256 results in the displacement counter
being decremented 258. The maximum value is again stored in RAM
260. Having polled the optical sensor 248, the system polls the
brake switch 262. If it receives a signal from the brake switch 264
it will assume that the faulty brake switch has been replaced. It
then recalculates the new parameters based on the trigger point of
the new brake switch 266. It then saves these parameters to
non-volatile memory 268 and disables the backup mode 270, thereby
ending the brake switch backup learn function 272.
[0047] Although an optical brake sensor is used in this embodiment,
it is to be understood that any other appropriate sensor means can
be used to sense the degree of application of the brakes.
[0048] Thus, for instance, a speed transducer attached to the
speedometer cable on the output drive of the gear box or a direct
input into the control module from the speed transducer of a
vehicle that does not have a speedometer cable, can be used.
[0049] Likewise, a strain gauge can be fitted to the brake pedal to
measure strain applied on the brake pedal during braking. Strain
gauges can also be fitted to other components that might be acted
upon when the brake pedal is moved.
[0050] Further, a pressure transducer or sender unit can be fitted
onto the master cylinder or brake lines to measure actual braking
pressure.
[0051] Alternatively, a derivative of the preferred optical sensor
can be configured in such a way that the sensor arrangement
consists of a bar with apertures or holes defined therein which are
arranged to move past the two emitters and receivers as previously
discussed.
[0052] Finally, resistance type sensors could be used. An example
of this would be a potentiometer, which is configured in a similar
manner to the optical sensor, but the infrared emitters and
receivers are replaced with a potentiometer. A change in the
resistance on the potentiometer will thus cause a change in voltage
and current which in turn can be detected by the control module,
and the data processed accordingly.
[0053] Once again, although a control module using a
microcontroller is preferred as it is software programmable, a
control module without a microcontroller can be used. A
microcontroller is, however, preferred as the system can be
upgraded by simply upgrading the software, providing greater
flexibility.
[0054] Referring to the brake light display, it is to be understood
that although a linear display arrangement having individual LEDs
is preferred, any other appropriate light arrangement can be used
provided the lights or light units light up in a sequence or
progressively in relation to application of the brakes.
[0055] It is believed that the progressive brake light system of
the invention provides a number of advantages over existing brake
light systems. The brake light indicator not only acts a third
brake light, it also provides an indication of the degree of
application of the brakes of a vehicle. Accordingly, the driver of
a following vehicle is in a better position to determine how hard
the brakes of his or her vehicle are to be applied. Further, the
brake light system of the invention can be tailored to a particular
vehicle and to any changes to its braking profile during the life
of the vehicle.
* * * * *